This invention relates to surface acoustic wave (SAW) substrate members of berlinite, AlPO.sub.4, having improved temperature compensation.
U.S. Pat. Nos. 4,109,172 and 4,109,173 to O'Connell provide background information relating to surface acoustic wave devices, and cover specific cuts of berlinite. Dryburgh et al in U.S. Pat. No. 4,189,516 disclose an aluminum nitride SAW material, and Ito et al in U.S. Pat. No. 4,333,842 disclose various X-cut materials. Fisher in U.S. Pat. No. 4,313,070 shows a metal wedge for conducting Raleigh surface waves.
The temperature compensation characteristic of previously known cuts of berlinite have been parabolic.